I currently have a HP Proliant Microserver that has an AMD Athlon II Neo N36L Dual Core 1.3Ghz processor. I use this for remote downloading and to stream media around the house. It does the job pretty well.

Now, I want to build a mining rig. As the 5850 are the best price/performance cards then I would use these cards to mine with.

That essentially just leaves the CPU. I want to keep costs as low as possible so I am after a CPU which would be the same or better than the one in my server for streaming media.

I've already got HDD's, a PSU, RAM (see below) and a caseIt would also need a wireless card too because its going in the garage

All I really need recommending are the Motherboard and CPU. Would anyone be able to recommend me some?

All I really need recommending are the Motherboard and CPU. Would anyone be able to recommend me some?

It depends on whether you want to make some other use of the machine as well. For a mining-only solution I'd stick with some low-cost motherboard of a reputable brand (my favorites are Asus and Gigabyte) and purchase the cheapest compatible CPU, regardless if Intel or AMD. However, I'd think of some extensibility for the future, so I'd recommend giving a go to a motherboard with 2+ PCI-E 16slots. Remember the slots shall not be adjacent to each other, so you can fit two (or more) dual-height cards.